<template>
  <div class="spec-preview">
    <img :src="img||imgUrl"/>
    <div class="event" ref="event" @mousemove="handleMove"></div>
    <div class="big">
      <img :src="img||imgUrl" ref="big" />
    </div>
    <div class="mask" ref="mask"></div>
  </div>
</template>

<script>
export default {
  name: 'Zoom',
  props: ['skuInfo'],
  data() {
    return {
      img:''
    }
  },
  computed: {
    imgUrl:{
      get:function(){
       return this.$store.state.Detail.detailList.skuInfo?this.$store.state.Detail.detailList.skuInfo.skuDefaultImg : undefined
      },
      set:function(value){
          // console.log(value);
          this.img = value
          // console.log(this.img);
      }
    }
  },
  methods: {
    handleMove(event) {
      // 获取mask蒙版的donm元素
      const mask = this.$refs.mask;
      const big = this.$refs.big;
      // 计算出蒙版的距离:
      let x = event.offsetX - mask.offsetWidth / 1.78;
      let y = event.offsetY - mask.offsetHeight / 2;
      if (x <= 0) x = 0;
      if (x >= mask.offsetWidth) x = mask.offsetWidth;
      if (y <= 0) y = 0;
      if (y >= mask.offsetHeight) y = mask.offsetHeight;
      mask.style.left = x + 'px';
      mask.style.top = y + 'px';
      // 修改右侧大图的left和 | top
      big.style.left = -2 * x + 'px';
      big.style.top = -2 * y + 'px';
    },
  },
  mounted() {
    // $on 触发事件 第一个参数是回调,第二个参数是传的参数
    this.$bus.$on('changeimg',(imgUrl)=>{
      // 将默认的图片等于要点击的图片
      this.imgUrl = imgUrl
    })
  },
};
</script>

<style lang="less">
.spec-preview {
  position: relative;
  width: 400px;
  height: 400px;
  border: 1px solid #ccc;

  img {
    width: 100%;
    height: 100%;
  }

  .event {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 998;
  }

  .mask {
    width: 50%;
    height: 50%;
    background-color: rgba(0, 255, 0, 0.3);
    position: absolute;
    left: 0;
    top: 0;
    display: none;
  }

  .big {
    width: 100%;
    height: 100%;
    position: absolute;
    top: -1px;
    left: 100%;
    border: 1px solid #aaa;
    overflow: hidden;
    z-index: 998;
    display: none;
    background: white;

    img {
      width: 200%;
      max-width: 200%;
      height: 200%;
      position: absolute;
      left: 0;
      top: 0;
    }
  }

  .event:hover ~ .mask,
  .event:hover ~ .big {
    display: block;
  }
}
</style>